Population dynamics of Megapitaria squalida (Bivalvia: Veneridae) at Magdalena Bay, Baja California Sur, Mexico

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Main Author: Tanja Schweers
Format: Artículo científico
Language:en
Published: Universidad de Costa Rica 2006
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author Tanja Schweers
author_facet Tanja Schweers
contents Population dynamics of Megapitaria squalida (Bivalvia: Veneridae) at Magdalena Bay, Baja California Sur, Mexico Tanja Schweers Volker Koch Francisco Sinsel Duarte Matthias Wolff Biología México Veneridae intertidal Bahía Magdalena population dynamics The population dynamics of an intertidal population of Megapitaria squalida was studied from September 2002 to February 2003 in Bahía Magdalena, Mexico. To obtain information about the artisanal and recreational fishery of M. squalida, local fishermen at different parts of the bay were interviewed. Clam densities were determined at one unexploited and two exploited sites along perpendicular transects from the shore line. Average clam density was 2.01±1.41 ind/m2, densities did not differ significantly between the three sampling sites. The length-total mass relation was Mtot = 0.0001*SL3.1644 (r2 = 0.9804, n = 92) and the length-tissue mass relation was Mtis = 0.0002*SL2.7144 (r2 = 0.945, n = 92). Von Bertalanffy-growth parameters were determined using marked individuals. Strong interindividual and also seasonal differences in growth were observed. Average annual values were: K = 0.655, L∞ = 83 mm. Since M. squalida can reach a shell length of more than 135 mm in deeper waters, it is necessary to consider intertidal and subtidal populations separately. Average total mortality (Z) was 1.61 y-1. No fishing mortality was calculated because total mortality Z at the unexploited control site was higher than Z at the exploited sites. It appears that M. squalida migrates into deeper water with increasing shell length, as average shell length increased at lower tidal levels and marked specimens showed a clear migrationtowards deeper waters. As yet no overexploitation could be found in the study area 2006 artículo científico 0034-7744 https://www.redalyc.org/articulo.oa?id=44954334 en http://www.redalyc.org/revista.oa?id=449 Revista de Biología Tropical application/pdf Universidad de Costa Rica Revista de Biología Tropical (Costa Rica) Num.3 Vol.54
format Artículo científico
id redalyc_44954334
institution Redalyc
language en
publishDate 2006
publisher Universidad de Costa Rica
spellingShingle Population dynamics of Megapitaria squalida (Bivalvia: Veneridae) at Magdalena Bay, Baja California Sur, Mexico
Tanja Schweers
Biología
México
Veneridae
intertidal
Bahía Magdalena
population dynamics
Population dynamics of Megapitaria squalida (Bivalvia: Veneridae) at Magdalena Bay, Baja California Sur, Mexico Tanja Schweers Volker Koch Francisco Sinsel Duarte Matthias Wolff Biología México Veneridae intertidal Bahía Magdalena population dynamics The population dynamics of an intertidal population of Megapitaria squalida was studied from September 2002 to February 2003 in Bahía Magdalena, Mexico. To obtain information about the artisanal and recreational fishery of M. squalida, local fishermen at different parts of the bay were interviewed. Clam densities were determined at one unexploited and two exploited sites along perpendicular transects from the shore line. Average clam density was 2.01±1.41 ind/m2, densities did not differ significantly between the three sampling sites. The length-total mass relation was Mtot = 0.0001*SL3.1644 (r2 = 0.9804, n = 92) and the length-tissue mass relation was Mtis = 0.0002*SL2.7144 (r2 = 0.945, n = 92). Von Bertalanffy-growth parameters were determined using marked individuals. Strong interindividual and also seasonal differences in growth were observed. Average annual values were: K = 0.655, L∞ = 83 mm. Since M. squalida can reach a shell length of more than 135 mm in deeper waters, it is necessary to consider intertidal and subtidal populations separately. Average total mortality (Z) was 1.61 y-1. No fishing mortality was calculated because total mortality Z at the unexploited control site was higher than Z at the exploited sites. It appears that M. squalida migrates into deeper water with increasing shell length, as average shell length increased at lower tidal levels and marked specimens showed a clear migrationtowards deeper waters. As yet no overexploitation could be found in the study area 2006 artículo científico 0034-7744 https://www.redalyc.org/articulo.oa?id=44954334 en http://www.redalyc.org/revista.oa?id=449 Revista de Biología Tropical application/pdf Universidad de Costa Rica Revista de Biología Tropical (Costa Rica) Num.3 Vol.54
title Population dynamics of Megapitaria squalida (Bivalvia: Veneridae) at Magdalena Bay, Baja California Sur, Mexico
topic Biología
México
Veneridae
intertidal
Bahía Magdalena
population dynamics
url https://www.redalyc.org/articulo.oa?id=44954334